Procalcitonin Patterns at Admission and Discharge in Moderate and Severe Hospitalised COVID-19: A Single-Centre Retrospective Study

Procalcitonin (PCT) was widely used in the COVID-19 pandemic to help distinguish virus-induced inflammation from secondary bacterial infection but its use in COVID-19 is still controversial, especially in hospitals lacking routine microbiological facilities. This study aimed to describe admission PCT levels alongside inflammatory, haematological and coagulation parameters in hospitalised patients with moderate and severe COVID-19. Historical discharge PCT measurements were also reviewed but they could not be verified and are not reported as results. This retrospective single-centre descriptive study included adults with PCR-confirmed SARS-CoV-2 infection admitted to a regional infectious diseases hospital in Bukhara, Uzbekistan, in 2020–2022 (moderate, n = 49; severe, n = 71), classified according to national guidelines and 20 adults without acute illness as a comparison group. PCT, C-reactive protein (CRP), ferritin, full blood count and coagulation parameters were measured at admission and discharge. This report is based on the aggregate results of the original doctoral dissertation (Bukhara State Medical Institute, 2024); individual patient records and original statistical output were not available for re-analysis. Data are presented descriptively as mean ± SEM, as labelled in the source tables. The significance results of the original analysis could not be verified and are not reported. Admission PCT was 0.39 ± 0.03 ng/mL in moderate and 0.75 ± 0.03 ng/mL in severe disease, compared with 0.03 ± 0.003 ng/mL in the comparison group. This severity-group difference is descriptive and was not tested; PCT was also among the supporting severity criteria, so it does not show an independent association with severity. CRP was almost identical across severity groups (19.6 ± 0.95 versus 20.3 ± 0.84 mg/L) and ferritin was lower in severe disease (186.23 ± 28.9 versus 242.6 ± 61.14 ng/mL). Discharge PCT values could not be verified, because the historical assay and its lower limit of quantification are not documented and the reported means were below 0.05 ng/mL; they are not reported as results. At discharge, mean D-dimer remained above the comparison-group mean but below the upper reference limit. In this aggregate data report, admission PCT was descriptively higher in severe than in moderate disease but this is not an independent association with severity. The discharge PCT values are unverified and do not support any conclusion. Without microbiological testing, these hypothesis-generating findings cannot distinguish bacterial involvement from severe virus-induced inflammation.